Used to be I would recommend Care.com....but I was a nanny listed (and getting jobs & working from) there for a long time (like 5 years) and ONE ex-friend of mine went on and made an anonymous "claim" about me & then poof I was banned. So, I don't recommend them anymore. She didn't pay for an account, and I wasn't her babysitter...she just did it to be mean.

I'd see who your friends are using & start there. Check with your church or a local one if you don't have one...they might have college aged kids available. My church keeps a directory of "businesses" of the people in the congregation & babysitters/day-care providers are listed.

I found my regular babysitter at the gym. She worked in the baby room. She's a college kid and is part of my family now. Our other one is a teenager boy from next door. His mom watched my oldest full time for almost 2 years so he is family too. I'm lucky :-)